certainty vs hang-up

certainty

noun
  • The state of being certain. 

  • A fact or truth unquestionably established. 

  • An instance of being certain. 

hang-up

noun
  • An unforeseen obstacle to progress; a hitch or delay. 

  • An emotional difficulty or a psychological inhibition; a complex. 

How often have the words certainty and hang-up occurred in a corpus of books? (source: Google Ngram Viewer )